The many types and forms of textile materials have one thing in common: almost all such fabrics are passive, and do not respond or interact by active human control with the environment into which they are placed. Typically, technical textiles are prepared from low volume, high value specialty synthetic fibers, while wearable (fashion) textiles are prepared from high volume low value natural or synthetic fibers. If electronic function could be integrated with technical or wearable textiles, then a new generation of devices would be possible. However, suitable conducting and semi-conducting textile fibers are scarce. There is therefore, a need for fibers that conduct electricity like a metal or an inorganic semiconductor, while simultaneously being compatible with conventional textile processing equipment. Such fiber must be mechanically strong and flexible, yet also be environmentally stable throughout the lifetime of the fabric.
Multifunctional electronic fabrics (Smart Fabrics and Interactive Textiles) can potentially revolutionize the way in which people interact with their daily environment. However, electronic devices would have to be brought into close proximity to the human body. Environmental stimuli (data) would be sensed or detected and collected through a variety of sensors at different locations of the fabric. The data collected from the body (or environment) would then be sent to a signal-processing unit (controller) for interpretation and, after a controlled response is achieved, information would be sent to other areas of the fabric (or an external device) to achieve a desired outcome from a functional device.
Organic semiconductors, variously called π-conjugated polymers, conducting polymers, or synthetic metals, are inherently semi-conductive due to π-conjugation between carbon atoms along the polymer backbone. Their structure contains a one-dimensional organic backbone based on the alternation of single and double bonds, which enables electrical conduction following n− or p+ type doping. Such materials offer advantages for sensor technologies, including the ability to tailor structure and properties, relatively low cost, and simple fabrication techniques; for example, they can be coated onto various types of substrates. These materials also have properties traditionally associated with other inorganic materials, including light absorption and emission; electrical conductivity; humidity, temperature, and pressure sensitivity; and electrochromic behavior. Unlike other conductive fiber materials that have been successfully woven by textile manufacturing equipment, such as metal wire (heavy, fabric, not washable), carbon or metal-filled plastic fiber (mechanical properties degrade with increased loading), graphite fiber (too stiff and brittle), and piezoelectric fiber (poorly conducting), conducting polymer fibers such as polyaniline are strong (strength modulus 2-6 GPa, tenacity 80-300 MPa), light weight (1.5 g/cm3), flexible (between 3% and 20% elongation), and highly conductive (300-1000 S/cm), making them suitable for weaving, knitting, stitching, and braiding.
Accordingly, it is an object of the present invention to provide wearable electronic textiles containing embedded wired, wireless and/or hybrid sensors, and distributed sensor networks (DSN) for sensing humidity, temperature, applied load (stress) and dimensional changes (strain), as examples.
Another object of the present invention is to provide sensor and DSN fabric for monitoring breathing rate, heart rate, blood emission (wound location), blood pressure, humidity, weight, movement, and skin temperature (for predicting the onset of hyperthermia and hypothermia).
Yet another object of the invention is to provide fabric having multifunctional capability.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.